In this paper, equivalent circuit models are first presented for characterizing the CPW SSPPs with etched slot. The asymptotic frequency and dispersion are investigated based on the theoretical model. And the analyses reveal that both the asymptotic frequency and dispersion curve can be manipulated by changing the inductance brought by the etched slots and the capacitance of the loaded capacitors. To validate the propagation performance, the proposed SSPP structure was fabricated and tested. The experimental results are consistent with the theoretical analysis, indicating that the designed SSPP structure possesses excellent low-pass filtering characteristics. Compared with traditional SSPP structures, the proposed structure exhibits a much narrower transversal width and does not require mode-conversion structures.

This article introduces a planar monopole antenna specially designed for NB-IoT module devices. The preferred choice for Internet of Things (IoT) technology is the Narrow-Band Internet of Things (NB-IoT) due to its extensive coverage and low power consumption. NB-IoT is specifically designed for IoT applications. A circular patch antenna with dimensions of 30 mm×60 mm is fabricated, which is specifically tailored for the NB-IoT module. The antenna dimensions are meticulously chosen to ensure compatibility with the device module, considering the NB-IoT B1 (2100) and B3 (1800) frequency bands. Among various patch shapes, the circular design is preferred for its advantages over hexagon and square patches. The desired antenna configuration combines a square-slotted patch with a monopole ground plane, and it offers several advantages in terms of design simplicity, compact size, and characteristics such as broad bandwidth, acceptable gain, and high radiation efficiency. The design process employs HFSS Software and utilizes an FR4 substrate of 1.6 mm thickness. Operating at resonance frequencies of 2.1 GHz and 1.8 GHz, the antenna covers a broad frequency spectrum of 1100 MHz (1.5 to 2.6 GHz) with a fractional bandwidth of 53.65%. The suggested antenna achieves a peak gain of 3.3 dB and maximum radiation efficiency of 96% within its operating band. It exhibits an omnidirectional radiation pattern, meeting the specific requirements of NB-IoT technologies. Experimental measurements of the fabricated antenna validate the results achieved from the simulated data.

This research article introduces a compact wearable antenna designed specifically for medical applications. The antenna underwent prototyping using a flexible Rogers Duroid RO3003^TM material, featuring a small form factor measuring 35 × 32 × 0.5 mm³. In the initial phase of the design process, a basic P-shaped rectangular patch antenna was employed. However, during the first design iteration (Design 1), the antenna demonstrated a single resonance around 1.2 GHz, although it was not optimally matched at that frequency. To tackle this problem and achieve miniaturization involved the introduction of two rectangular patches positioned below the P-shaped patch known as Design 2. To further improve its performance, an inverted L-slot was incorporated. The frequency of operation for the antenna is 2.4 GHz, with a bandwidth measuring 25.2% ranging from (2.087-2.692) GHz. The measured radiation patterns demonstrate bidirectional properties in the E-plane and omnidirectional properties in the H-plane and maintain a high gain of 3.54 dBi and an efficiency of 91%. The SAR values are 0.018/0.013 Watt/kg on the chest. Similarly, the SAR values are 0.02/0.015 Watt/kg on the thigh, using 1/10 g of human tissue, which comply with the standards set by the FCC and the ICNIRP. Furthermore, the simulation and measurement under bending investigation and being close to the human body demonstrate excellent performance. Therefore, the suggested antenna holds significant potential as a compact solution for wearable medical applications.

Micro Deformation Monitoring Radar has been widely used in the field of surface deformation and displacement monitoring. However, limited by radar imaging geometry, the deformation measurement by existing radar technology can only extract the deformation and displacement of the target line of sight (LoS), which cannot directly reflect the actual deformation and displacement of the landslide direction and easily results in misjudgment or omission of the surface deformation monitoring information. In this paper, the relationship model and mapping between radar data and three-dimensional coordinate system were analyzed to perform three-dimensional analysis of the LoS displacement. Combined with the landslide displacement direction, the mapping angle between the LoS direction at any point in the observation area and the landslide direction was solved, and then the deformation displacement in the landslide direction was obtained by solving the LoS direction displacement. Finally, taking the measured data of one slope as the research object, the feasibility and accuracy of the method were analyzed and verified. The conclusion shows that the method proposed in this paper can be effectively applied to calculate the true value of landslide deformation.

Utilizing deep learning to replace numerical simulation solvers for electromagnetic wave propagation is a promising approach for the rapid design of photonic devices. However, to realize the advantages of deep learning for rapid design, it is essential to apply it to a general device structure. In this study, we propose a method that employs deep learning to assist in fast design of a general grating coupler structure. We use a modified 1D-ResNet18(1D-MR18) to predict the coupling efficiency of various grating couplers at different wavelengths. After comparing and selecting the optimal combination of learning rate, activation functions, and batch normalization size, the 1D-MR18 demonstrates remarkable accuracy (MSE: 2.18×10^-5, R²: 0.969, MAE: 0.003). By integrating the 1D-MR18 with the adaptive particle swarm algorithm, we can efficiently design periodic and nonuniform grating couplers that meet various functional requirements, including single-wavelength grating couplers, multi-wavelength grating couplers, and robust grating couplers. The time for designing a single device is no more than 2 minutes, and the shortest is only 17 seconds. This novel approach of employing deep learning for the fast and efficient design from standard photonic device structures offers valuable insights and guidance for photonic devices design.

In this work, a novel time domain Transmission Line Matrix (TLM) algorithm with Symmetrical Condensed Node (SCN) is developed to model electromagnetic (EM) wave propagation through a single graphene layer in Terahertz (THz) spectrum. The intraband conductivity of graphene (assumed to follow the Drude model) is implemented in TLM method by using the Auxiliary Differential Equation (ADE) of conduction current density. The validity and stability of the obtained results demonstrates the effectiveness and precision of this new modeling technique named ADE-(SCN)TLM, and prove that this method is a powerful tool that can be used to model and simulate complex devices based on graphene sheet for terahertz applications (e.g., Electronics, optoelectronic, ect.).

The linear sampling method (LSM) is a qualitative inverse scattering technique for reconstructing the shape of a target. It has several beneficial qualities, including the avoidance of nonlinear optimization and simplified scattering approximations. However, it often struggles when sensors can only be placed on one side of the target. In this paper, we investigate two alternative LSM formulations for overcoming the limited-aspect challenge. The first, the phase-delay frequency variation LSM (PDFV-LSM), incorporates coherent processing across frequency to improve discrimination in the range direction. The second, the phase-encoded LSM (PE-LSM), enhances the PDFV-LSM approach with a receive-beamforming operation to decrease the complexity of the inverse problem. We apply both techniques to simulated data from three-dimensional targets and three-dimensional limited-aspect arrays. We generate three-dimensional reconstructions and compare them to reconstructions from both the conventional LSM and conventional backprojection-based processing. The results demonstrate superior reconstruction fidelity for either the PDFV-LSM, the PE-LSM, or both, across a wide variety of imaging scenarios due to finer range resolution. They also demonstrate trade-offs between the two enhanced LSM techniques, with the PE-LSM achieving better range resolution and robustness to noise and the PDFV-LSM achieving better lateral resolution.

A miniaturized and closely packed eight element annular ring multiple-input multiple-output (MIMO) antenna array is designed to operate from 3 to 6 GHz band for 5G smartphone applications. In MIMO, the orthogonally placed antenna pairs maintain high isolation. The proposed decoupling structures placed between two adjacent antenna pairs improve the isolation. The decoupling structure consists of a rectangular metallic strip with metallic vias that reduces the mutual coupling and excites the additional modes to extend the bandwidth from 3 to 6 GHz. The MIMO structure offers isolation of more than 24 dB, ECC of less than 0.1, TARC of less than 7 dB over the complete operation band, DG of 10 dB, and more than 95% efficiency. The specific absorption rates (SARs) of the antenna placed in the human head and hand models are 0.41 W/Kg and 0.66 W/Kg, respectively. The performance obtained with the fabricated prototype offers excellent matching with that of the simulated ones.

The dual band notched features of an ultra-wideband (UWB) antenna are presented. The radiator element is a rectangular one with several slots. The planned antenna's operational frequency ranges from 2.8 to 10.6 GHz. By embedding a rectangular slot on the radiator and a folding stepped resonator in the ground plane, it is possible to create dual notched bands that are 3.76-5.9 GHz with a central frequency of 5.2 GHz (WLAN) and 2.85-3.32 GHz with a centre frequency of 3.2 GHz (WiMAX). The antenna measures 32 × 32 mm² across the board. In terms of VSWR, group delay, efficiency, and radiation pattern, the antenna's performance is confirmed. Results from simulation and testing of the stated antenna are closely matched.

A Mushroom-Cloud-shaped wide slot Microstrip patch antenna (MC-MSPA) was discovered and proved to be a viable option for Wideband applications in this research study. The given antenna has a high radiation and wideband reflection coefficient of 134.47% from 1.15 GigaHz to 5.87 GigaHz for |S₁₁|<-10 dB. This antenna has a peak gain of 6.47 dBi at 4.6 GigaHz and 6.1 dBi at 5 GigaHz, as well as an return loss of 47.37 dB at 1.88 GHz. MC-MSPA has optimised dimensions of 0.73λ_g×0.72λ_g×0.02λ_g. Furthermore, a reflecting surface of a 7×7 square-shaped array beneath the ground plane has been included to provide even higher gain and directivity. The proposed MC-MSPA+RP antenna has a fractional bandwidth of 63% with dual bands from 1.438 to 2.782 GigaHz and 38.89% from 3.964 to 5.878 GigaHz, with a peak gain of 9.657 dBi, maximum directivity of 10.44 dBi at 5 GigaHz, and maximum return loss of 54 dB at 4.9 GigaHz. Reflector plate electrical dimensions have been enhanced to 0.87λ_g×0.87λ_g×0.24λ_g. The proposed design improves gain and directivity, both of which are important for WLAN and Wi-MAX applications.

The exponential increase of data traffic in next generation wireless communication attracts optimized design of antenna arrays (AAs) to be deployed in RANs. The traditional antenna array synthesis techniques have become exhaustive leading to the introduction of machine learning assisted new binary optimization algorithm. In this paper, three specific AA features are given particular attention: peak sidelobe level (PSLL), first null beam width (FNBW), and broad sector null in interference directions. These contrast each other, and a multi-objective new binary cat swarm optimization (MO-NBCSO) with a novel mutation probability is developed to derive the best-compromised solutions among them. The computational complexity is approximated as O(MN²) (here, M and N represent the number of objectives and population size, respectively). Hence, a 20×20 planar antenna array is considered for synthesis and pareto fronts are generated alongside state-of-the-art MO algorithms. A fuzzy-based decision approach is introduced to choose the best trade-off solutions. A detailed comparative performance study is carried out by the two-performance metrics, namely, I-metric and S-metric. Numerical results illustrate that MO-NBCSO is a better candidate to produce the best antenna arrays in terms of array characteristics over other algorithms.

In this letter, a novel 3-D heterogeneous solenoid inductor with high inductance value is proposed. By adding planar spiral structure at the ends of through-silicon vias (TSVs) of typical 3-D solenoid inductor, the heterogeneous solenoid is formed. The total inductance is increased by more than 41% compared with that of typical solenoid inductor of the same size. Additionally, an accurate analytical model of the inductor is established considering all the factors including angle and offset. Q3D simulation results verified the accuracy of the model, and the percentage error is less than 5.38%. This work provides an important reference for inductor designers to quickly estimate inductance value, configuration, and layout area.

In this paper, we developed a hyperspectral transmission microscopic imaging (HTMI) system for rapid detection of pathogenic bacteria, which can realize precise identification and classification of mixed pathogenic bacteria to a single-bacterium level. The system worksin trans-illumination patterns and a self-developed dispersive hyperspectral imaging module is usedas the detection setup, providing spectral images with high SNR, and showing excellent performances with spatial resolution of 2.19 µm and spectral resolutions less than 1 nm. Hyperspectral microscopic imaging of five types of bacteria in low concentration were performed. The merging spatial-spectral profiles of individual bacteria for each species were extracted and utilized for species identification, achieving high classification accuracy of 93.6% using a simple PCA-SVM method. Species identification experiments of the mixed bacterial sampleswere further carried out, and the results demonstrate the validity and capability of the system assisted with simple machine learning methods to be used as an effective and rapid diagnostic tool for elaborate identification of mixed bacterial pathogen samples, providing guidance for the use of correct antibiotics.

In this paper, several multiband patch antennas with sinc-shaped edges were analyzed, designed, simulated and implemented for modern sub-6 GHz applications. The aim is to use the sinc function parameters such as amplitude and number of maxima (frequency) to control the antenna performance such as resonance and radiation characteristics. It is shown that changing the sinc pattern parameters has a significant impact on the resonance of the antenna, and hence these parameters can be used to directly control the multiband behavior of the antenna. The proposed antenna designs were manufactured, and their performance was tested experimentally in the lab and compared to simulation results. An acceptable agreement between experimental and simulated results was achieved.

The performance of the Vertical Cavity Surface Emitting Laser (VCSEL) for hybrid optical links SMF/FSO based on different data rates and MIMO configuration techniques was obtained using OptiSystem^TM which is close to the results of the experimental system. The developed system was tested with various transmission distances: 20, 30, 40, and 50 km, and in the existence of many configuration kinds and modulations. In addition to that the hybrid system was estimated with different weather cases: clear, rain, and snow. The results state that the performance of the OOK-NRZ system reveals better performance than OOK-RZ system under the same conditions. Also, the performance of the free space link is better than the fiber link formost of the link ranges considered and configurations. For OOK-NRZ of the fiber link, it was found that the MIMO 8×8 technique has better system performance than other configurations, and the Q-factor = 11.39 and BER = 5.4×10^-30 for a length of 50 Km while for the FSO link, it was found that MIMO 8×8 indicates a high performance for Q-factor = 12.7 and BER = 1.8×10^-37. The maximum FSO link distances under different weather conditions and coupling ratios were found. For BER≤10⁻⁹, in NRZ format for SMF 50 km utilizing MISO8×1 technology in clear weather for 10 Gbps, 15 Gbps, and 20 Gbps for FSO links, the maximum accessible lengths are 0.6 Km, 0.51 Km, and 0.43 Km, respectively. The process is expanded to include snow conditions for data rates of 10 Gbps, 15 Gbps, and 20 Gbps for FSO links with lengths of 0.4 Km, 0.3 Km, and 0.26 Km, respectively.

Methods of manual analysis for infrared image and temperature detection of power transmission and transformation equipment typically have problems, such as low efficiency, strong subjectivity, easy to make mistakes and poor real-time feedback. In this paper, a high temperature anomaly detection method based on SegFormer in infrared image of power transmission and transformation equipment is proposed. Many infrared images of power transmission and transformation equipment are collected and preprocessed, and the temperature information of each infrared image is read out using the DJI sdk tool to construct the temperature data matrix. In the segmentation stage, the SegFormer network is used to segment the key parts of the power transmission and transformation equipment to obtain the mask for detection. The maximum values of the temperature data in the mask area are calculated, and the high temperature anomaly detection atthe key parts of the power transmission and transformation equipment is realized. The test results on the test set show that the overall performance of the method is the highest as compared to other methods such as FCN, UNet, SegNet, DeepLabV3+, and an automatic temperature recognition can be realized, which has important practical value for the detection of high temperature anomaly at the key parts of power transmission and transformation equipment.

This paper designs a miniaturized, wide stopband microstrip filtering coupler based on coupled resonators. Firstly, a short-stub loaded uniform-impedance resonator (SSLUIR) is proposed, , and the size of the SSLUIR is reduced by adjusting the impedance ratio of the stubs and bending them. Then, the resonance performance of SSLUIR during electrical and magnetic coupling is studied. By adjusting the electrical length of the short stubs, higher harmonics are suppressed, and the upper stopband is widened. Finally, a 3 dB 180° microstrip filtering coupler is designed based on SSLUIRs. The measurement results show that the center frequency of the filtering coupler is 2.43 GHz, with a relative bandwidth of 6.6%. It can suppress harmonics within the 8.2f₀ range by more than 18 dB and has a size of 0.23λ_g×0.33λ_g. The correctness of the design method for miniaturized and wide stopband filtering coupler has been verified.

Plasmonic topological states, providing a new way to bypass the diffraction limits and against fabrication disorders, have attracted intense attention. In addition to the near-field coupling and band topology, the localized surface plasmonic resonance modes can be manipulated with far-field degrees of freedom (DoFs), such as polarization. However, changing the frequency of the topological edge states with different polarized incident waves remains a challenge, which has led to significant interest in multiplexed radiative topological devices. Here, we report the realization of polarization-wavelength locked plasmonic topological edge states on the Su-Schrieffer-Heeger (SSH) model. We theoretically and numerically show that such phenomenon is based on two mechanisms, i.e., the splitting in the spectra of plasmonic topological edge states with different intrinsic parity DoF and projecting the far-field polarizations to the parity of lattice modes. These results promise applications in robust optical emitters and multiplexed photonic devices.

This paper presents a novel design of Compact Notched Wide Band Antenna that has dual notches in the band of Wireless Local Area Network (5.15 GHz-5.825 GHz) and X-band Satellite Communication (8 GHz-12 GHz). The proposed antenna has a defective ground structure (DGS) to operate the antenna for wide band applications. Notch bands are achieved by inserting slots on the radiating patch and feed line. A horizontal S-shaped slot on patch is responsible for the notch in the band of wireless local area network, and an inverted U slot is used in feed line to get a notch in the band of Satellite Communication. The proposed antenna is fabricated using FR4 substrate of size 26 x 26 x 1.6 mm³ and tested using Vector Network Analyzer MS2037C. Although the measured results are slightly changed in comparison with simulated, they agree reasonably well. The measured result also reveals that the prototype antenna is in compact size and resonated from 4.24 GHz-12.59 GHz with two notch bands centered at 5.8 GHz and 10.3 GHz.

Wireless communication systems have developed significantly over the last few decades. Due to the saturation of lower frequencies of microwave spectrum (3-30 GHz) and the increasing need for high speed, emerging systems for consumer or professional use are progressively shifting to upper microwave and millimeter waves. Our study proposes a methodology for evaluating and classifying losses on a vertically polarized millimeter wave link at 80 GHz. To achieve this, we simulated the link budget of a Nokia 80UBT millimeter wave link operating in its real propagation space (with overground) with Pathloss 5.1 Design tool. Then we built a 3.58 km full-scale link in the Tongo-Bassa watershed of the coastal city of Douala in Cameroon. Analysing data collected over the period from December 06, 2020 to December 16, 2021 under Power BI allowed us to characterize the response of the millimeter signal in free space, during dry and rainy seasons. We then challenge ITU-R P.837-7 and ITU-R.P.838-3 Recommendations on statistical models of rainfall for propagation modeling, especially for millimeter signals propagated in an equatorial climate with heavy rainfalls. The study estimated a rainfall rate for 0.01% of the time at 110.1 mm/h, with a millimeter link cut-off for a rainfall rate greater than 64.8 mm/h, with a specific attenuation due to rain of 6.5 dB/km.